Buoyancy and Wind Driven Changes in Subantarctic Mode Water During 2004–2019

The Subantarctic Mode Water (SAMW) is a thick low-stratified subsurface water mass located north of the Antarctic Circumpolar Current, and it important for heat uptake. How SAMW has changed what drives that change remain to be quantified. By synthesizing observations, eddy-resolving ocean model hindcasts climate simulations, we show become warmer, fresher, lighter, weaker in recent decades. As revealed by partially coupled experiments, core remained at constant depth since 2004 due balance between enhanced wind stress curl, which deepens core, buoyancy gain, shallows core. lightening weakening mainly result from increased surface gain warming, while westerlies play secondary role slowing this trend. greenhouse warming continues, stratification will keep SAMW.